Ever get the feeling that the Chesapeake Bay is trying to tell you something?

To get it, go online to a Google Maps image of the bay, and zoom in on a patch of water a few miles north of the Chesapeake Bay Bridge. There's a pattern of blue and green patches that coalesces into a shape.

"It really, almost, looks like a skull," said Kim Couranz of the National Oceanic and Atmospheric Administration.

It looks like a green skull the size of Baltimore.

There are so many tantalizing possibilities here: Is the Chesapeake death's-head a large algae bloom? A signal of impending doom? An ingeniously placed ad for "Indiana Jones and the Kingdom of the Crystal Skull"?

The actual cause, as usual, turns out to be the least exciting.

According to Google, the skull is probably a computer glitch.

Chikai Ohazama, who oversees mapmaking operations at the Internet giant, said the skull never actually appeared in the water. Instead, he said, it was created by accident on a computer as Google technicians digitally combined two satellite photos of the same area.

"I'm sure they just missed" the skull shape that was produced in the combined image, Ohazama said.

Ohazama said that the image had probably been up for a year at least and that there were no plans to remove it. He said there was no evidence that anyone at Google had drawn the skull on purpose.